I've noticed there is some difference between saying someone is autistic vs. saying they have autism.
In spanish, the english "to be" verb is translated as "ser" (related to the self) and as "estar" (temporary and subjet to change state).
For spanish it is confusing that you make no distintions between the both. Lets put some examples:
Peter is angry. -> Its something temporal, so Peter "estar" angry.
Peter is tall -> Its something permanent, so Peter "ser" alto.
So whats the difference between:
Peter "ser" fat
and
Peter "estar" fat
In the first one we consider it to be permanent and related with the self, in the second one we consider it something temporal subjet to change. In english it is confusing. We cant easily know if they say the person is fat in temoral or a permanent way. The verb "to be" is not clear enougth.
The same happens with Autism.
People who consider Autism to be an illness and who looks for a cure will consider Autism to be temporal. So thats why they use "have" instead of using "to be". Like they "have" an illness. Thats why ABA guys are forced to use "have":
At work, we are required to say they "have Autism" and never "are autistic."
On the other hand, people who consider Autism to be a permanent part of the self will use the verb "to be" in the same way spanish use the verb "ser". And by using language that way they kind of defend Autism being a neurodivergence and not an illness.
The spectrum is so variated that people with heavy problems related to Autism may actually consider it some kind of illness, even if it is a generic stuff. Like other genetic "Syndromes".
While more "functional" people are more to consider themselves as a healthy divergence to the norm and thus dislike the "Syndrome" term and the illness related use of the language.
Its difficult to use the same language to reffer to such a different group of people.